JP4055098B2 - Radio wave absorbing precast concrete board and manufacturing method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a radio wave-absorbing precast concrete plate that uses a cross-shaped ferrite magnetic material to prevent reflection interference such as television radio waves and a method for manufacturing the same.
[0002]
[Prior art]
If the situation which blocks the electromagnetic waves flying around by the building is formed, the electromagnetic waves are reflected on the building and secondary noise is generated in the surrounding area to newly generate electromagnetic interference.
At present, television radio waves exist as electromagnetic waves constantly flying around buildings, and the frequency used for both VHF and UHF television radio waves forms a wide frequency band of 90 to 770 MHz. And when a high-rise building was constructed, the TV radio waves reflected on the building would have an effect over long distances, causing radio interference such as ghosts over a wide area.
[0003]
For this reason, with regard to TV radio wave reflection and shielding obstructions, countermeasures for TV radio wave interference have been studied in high-rise buildings.
Among the obstacles to television radio waves, various countermeasures have been conventionally taken because the affected area is a long distance and wide area.
As a measure to absorb radio waves without reflecting them, the exterior wall made of precast concrete (hereinafter abbreviated as “PC”) with ferrite tiles is adopted for the outer wall surface in consideration of industrialization of the construction. Thus, many methods have been adopted to give buildings the ability to absorb electromagnetic waves.
[0004]
For example, as shown in FIG. 7A, the conventional radio wave absorption PC plate 30 has tiles 32 arranged on a bottom surface 31a of a mold 31 and a ferrite plate 33 is directly set on the back surface of the tiles 32. The grid-like reflective reinforcing bars 34 are arranged, and then concrete 35 is placed in the mold 31 for manufacturing. At this time, ridges 32 a and 32 a are formed on the back surface of the tile 32 to securely attach the tile 32 to the concrete 35. Also, there is a similar method in which an anchor 36 is provided on the back surface of the tile 32 ′ as shown in FIG. 7B.
[0005]
As another method, as shown in FIG. 8, flat tiles 37 are arranged on the bottom surface 31 a of the mold 31, and then a mortar 38 is placed on the top surface, and a ferrite plate is placed on the top surface of the mortar 38. After the 33 and anchor bars 39 are partially embedded and set, the reinforcing bars 34 and the concrete 35 may be placed.
[0006]
[Problems to be solved by the invention]
However, since ferrite tiles have a narrow frequency band for absorbing electromagnetic waves, they have been prepared for different sizes and arrangements for VHF and UHF. Improvements are desired, and not only for specific electromagnetic waves such as horizontally polarized TV waves, but also for all electromagnetic waves that are not related to horizontal and vertical via an artificial satellite. Is expected.
[0007]
Moreover, the following problems exist in the manufacturing method of the conventional electromagnetic wave absorption PC board mentioned above.
That is, in the method using the tile 32 shown in FIG. 7A, since the protrusion 32a must be formed on the back surface of the tile 32, the manufacturing cost of the tile 32 becomes high, which increases the cost of the radio wave absorption PC board. There is a problem of inviting. Further, in the method using the tile 32 ′ shown in FIG. 7B, the anchor 36 is provided on the back surface of the tile 32 ′. To fix the anchor 36 to the tile 32 ′, a hole is formed on the back surface, etc. In this case, the manufacturing cost is high. Moreover, there is a problem that it is difficult to fix the anchor 36 when the tile 32 'is thin.
[0008]
Furthermore, in the method shown in FIG. 8, since the flat tile 37 is used, the above-mentioned problem can be avoided. However, since the two layers of the mortar 38 and the concrete 35 are used, it takes time and productivity is poor. There is a problem of becoming. In addition, since the radio wave absorption performance is affected by the moisture content of the mortar 38 present on the front surface of the ferrite plate 33, it takes time to dry the mortar 38, and the productivity is also deteriorated from this point.
[0009]
The present invention has been made in view of the above problem awareness, and efficiently absorbs electromagnetic waves such as TV radio waves to prevent radio wave interference due to building reflections, and is lightweight and inexpensively manufactured as a building exterior material. An object is to provide a radio wave absorbing PC board that can be produced and a method of manufacturing the same.
[0010]
[Means for Solving the Problems]
The radio wave absorption PC plate according to the invention of claim 1 includes a cross-shaped radio wave absorber , a mortar layer forming a surface of a radio wave absorption precast concrete plate disposed in front of the cross-shaped radio wave absorber , and the cross-shaped radio wave absorption Body and concrete that embeds the mortar layer, and anchor bars having one end embedded in the mortar layer, and the cross-shaped wave absorber includes a plurality of cross-shaped ferrite magnetic bodies disposed on a radio wave reflector. Configured so that the length direction of the cross-shaped ferrite magnetic body is substantially parallel to the magnetic field direction of the television radio wave, and the height, thickness, and interval values of the cross-shaped ferrite magnetic body are set as the wavelength of the television radio wave. It is set to a predetermined value in relation to the incident angle and the mortar layer on the front surface of the ferrite magnetic body, and the interval between the plurality of cross-shaped ferrite magnetic bodies is maintained by the gap filler. To.
[0011]
The radio wave absorption PC plate according to claim 2 is the radio wave absorption PC plate according to claim 1, wherein the plurality of cross-shaped ferrite magnetic bodies are arranged in parallel on the radio wave reflection plate. .
[0012]
The radio wave absorption PC plate according to claim 3 is the radio wave absorption PC plate according to claim 1, wherein the plurality of cross-shaped ferrite magnetic bodies are arranged in a grid pattern on the radio wave reflection plate. To do.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
The radio wave absorption PC plate according to the present invention basically includes a cross-shaped radio wave absorber, a mortar layer forming a surface of the radio wave absorption PC plate disposed in front of the cross-shaped radio wave absorber, a cross-shaped radio wave absorber and a mortar layer. It is made of concrete that embeds the wall and efficiently absorbs electromagnetic waves to prevent radio interference caused by building reflections.
Embodiments of a radio wave absorption PC board according to the present invention will be described below with reference to the drawings.
[0018]
FIG. 1 is a perspective view of a radio wave absorption PC board according to the present invention.
The radio wave absorption PC plate 1 is a state in which a cross-shaped radio wave absorber 2 and a mortar layer 5 forming the surface of the radio wave absorption PC plate 1 are embedded in the concrete 3 with the front surface 4 of the mortar layer 5 left. Has been built.
The cross-shaped wave absorber 2 is fixed to the upper surface of the mortar layer 5 with an elastic adhesive (not shown) or the like. Furthermore, anchor bars 6 are implanted in the mortar layer 5, and one end side is embedded in the mortar layer and the other end side is embedded in the concrete. Therefore, the cross-shaped wave absorber 2, the mortar layer 5, Is firmly bonded to the concrete, and the electromagnetic wave absorbing PC board has sufficient strength.
Note that tiles, stones, or the like can be attached to the front surface 4 of the mortar layer 5 or sprayed, and the surface finishing material of the radio wave absorption PC plate 1 can be configured.
[0019]
FIG. 2 is a perspective view of a panel unit constituting the radio wave absorption PC board according to the present invention, and FIG. 3 is an elevational sectional view of the panel unit.
As shown in FIGS. 2 and 3, the panel unit 10 includes a mortar layer 5 that forms the surface of the radio wave absorption PC plate, a strip-shaped bar-shaped radio wave absorber 2 that extends in one direction, and an anchor bar 6. The front surface 4 of the mortar layer 5 forms the surface of the radio wave absorption PC plate 1.
[0020]
The mortar layer 5 is formed to have a predetermined thickness, whereby the cross-shaped wave absorber 2 and the anchor bar 6 are integrated. For example, fiber reinforced mortar, glass fiber mortar, vinylon fiber mortar, aramid fiber mortar, or the like is used for the mortar layer 5, thereby serving as a reinforcing material for the panel unit 10 that is long in one direction.
[0021]
The cross-shaped wave absorber 2 is fixed to the upper surface of the mortar layer 5 with an elastic adhesive (not shown) or the like. The mortar layer maintains the performance of the cross-shaped wave absorber 2 by reducing the water content by sufficient drying so that the electromagnetic characteristics are as close to air as possible.
[0022]
The anchor muscles 6 are disposed on both sides of the cross-shaped wave absorber 2 along the longitudinal direction. As shown in FIG. 3, each anchor bar 6 extends integrally with the connecting bar 6 </ b> A provided at predetermined intervals along the longitudinal direction of the cross-shaped wave absorber 2. And the lattice muscle 6B.
The connecting line 6A constituting the anchor line 6 is formed in a U-shape that crosses the cross-shaped wave absorber 2 and one end thereof is embedded in the mortar layer 5 on one side of the cross-shaped wave absorber 2. The other end is buried in the mortar layer 5 on the opposite side of the cross-shaped wave absorber 2.
Similarly, the lattice muscle 6B constituting the anchor muscle 6 is positioned in a plane extending along the longitudinal direction of the cross-shaped wave absorber 2 and orthogonal to the mortar layer 5, and its lower chord side is a mortar layer. 5 is buried.
[0023]
The connecting muscle 6A and the lattice muscle 6B are joined to the upper chord material 7 on the upper chord side, and joined to the lower chord material 8 on the lower chord side embedded in the mortar layer and integrated with each other. Forming. Such connection between the reinforcing bars further improves the overall strength of the mortar layer and the anchor bars, and is advantageous in handling when producing the radio wave absorption PC board.
In particular, the integral structure of the connecting bar 6A and the lattice bar 6B not only functions as an anchor bar to be integrated with the concrete to be placed later, but also serves as a reinforcing bar for the panel unit 10 that is long in one direction. Also fulfills the function.
[0024]
FIG. 4 is a partial elevation view (a) and an arrow view (b) for explaining the function of the radio wave absorption PC board according to the present invention.
As described above, the panel unit 10 constituting the radio wave absorption PC plate includes the mortar layer 5 that forms the surface of the radio wave absorption PC plate, the strip-shaped bar-shaped radio wave absorber 2 extending in one direction, and the anchor bars 6. It consists of and.
[0025]
As shown in the figure, the cross-shaped radio wave absorber 2 is configured by joining a rectangular parallelepiped cross-shaped ferrite magnetic body 11 on a radio wave reflection plate 12 which is a conductive metal body.
The cross-shaped wave absorber 2 and the mortar layer 5 are integrated by fixing the surface of the cross-shaped ferrite magnetic body 11 on the opposite side of the radio wave reflector 12 to the mortar layer using an elastic adhesive or the like. Are connected.
[0026]
The gap filler 13 is disposed between the cross-shaped ferrite magnetic bodies 11 in order to maintain the interval between the cross-shaped ferrite magnetic bodies 11. In this embodiment, a commercially available polystyrene or foam joint is used. However, as described later, since it is preferable that the electromagnetic wave absorption characteristics have a gap between the cross-shaped ferrite magnetic bodies, the gap filler 13 A material having a low moisture content and an electromagnetic property close to air is suitable.
Therefore, when the cross-shaped ferrite magnetic body 11 can adopt a fixing means that can withstand strength without providing the gap filler 13, it is characteristically advantageous that the gap filler 13 is not provided. Therefore, it is desirable to omit the gap filler 13 to form an air layer.
[0027]
The cross-shaped ferrite magnetic bodies 11 are ferrite magnetic bodies having a thickness t, a height h, and a length L, and are arranged in parallel with an interval s so that the longitudinal direction is the same direction.
In order to absorb radio waves, the electric field direction of the incident radio waves is arranged so as to be orthogonal to the longitudinal direction of the cross-shaped ferrite magnetic body 11, and the magnetic field direction of the radio waves coincides with the longitudinal direction of the cross-shaped ferrite magnetic body. Must be arranged to do.
Therefore, in the case shown in the figure, it corresponds to the horizontal polarization of TV radio waves, but in order to deal with all radio waves, crossed cross-shaped ferrite magnetic materials are additionally arranged in a grid pattern. Will be dealt with.
[0028]
The above-described configuration of the cross-shaped wave absorber 2 converts the radio wave into a TM wave and absorbs it without absorbing it as a TEM wave, similarly to a broadband ferrite radio wave absorber (see Japanese Patent Laid-Open No. 4-42999). Thus, if the above configuration is used as a transmission line model and the input impedance and the characteristic impedance of the transmission line are converted into an equivalent circuit, the desired impedance is obtained between the input impedance of the cross-shaped ferrite magnetic body 11, the wavelength λ of the operating frequency of the operating radio wave, and the characteristic impedance. If this relationship holds, a state of zero reflection exists.
[0029]
The input impedance of the cross-shaped ferrite magnetic body 11 can be adjusted by changing the material, such as the magnetic permeability and dielectric constant of the ferrite magnetic body, the shape regulated by the thickness t, height h, and length L, and the spacing s. Therefore, the state of zero reflection can be set by adjusting the input impedance of the ferrite magnetic material.
The mutual relationship between the thickness t, height h, length L of the ferrite magnetic body and the gap s to be disposed is selected as follows.
[0030]
Considering the state of the operating radio wave, since the ferrite magnetic body has a magnetic field focusing action, if the ferrite magnetic body is continuous in the direction of the magnetic field component of the operating radio wave, the gap in the electric field direction is hardly a problem. Based on a thickness t that does not deteriorate the magnetic field absorption characteristics.
[0031]
If the height h is changed while the thickness t and the gap s of the ferrite magnetic material are kept constant, the characteristics in the high frequency range can be improved at the sacrifice of the characteristics in the low frequency range with the predetermined value as the boundary. I understand. Therefore, in consideration of this characteristic, the rectangular parallelepiped is specified and adjusted in accordance with the target frequency range within the range of the ferrite magnetic body length L.
As for the gap s, it has been found that an optimum value exists in the value of t / s. Therefore, it is effective to adjust the gap s within the range of the wavelength λ of the incident radio wave that affects the gap.
That is, by configuring the shape and arrangement of the cross-shaped ferrite magnetic body 11 such that L ≧ h ≧ t and λ ≧ s ≧ t, the incident radio wave is absorbed in a wide frequency band, and the reflected radio wave is predetermined. It can be adjusted to attenuate below the level.
[0032]
In the case of TV radio waves, the frequency band is 90 to 770 MHz when the entire region of VHF and UHF is targeted. Therefore, it is necessary to absorb the frequencies of these bands and prevent reflection.
According to the experiment, when the attenuation rate due to the absorption of the TV wave is set to 15 to 25 dB, the width t = 5 to 10 mm and the height h = 16 to 22 mm of the ferrite magnetic body are adjusted in the range of the interval s = 15 to 40 mm. However, if arranged, it can be handled without substantially reflecting. However, the shape and spacing of the cross-shaped ferrite magnetic material are determined in relation to the frequency of the radio wave, the incident angle, and the electromagnetic characteristics of the nearby structural material. It is necessary to select appropriately from the above viewpoint.
[0033]
As described above, the radio wave absorption PC plate according to the present invention includes a cross-shaped radio wave absorber, a mortar layer that forms the surface of the radio wave absorption PC plate disposed in front of the cross-shaped radio wave absorber, and the cross-shaped radio wave absorber and mortar layer. Because it is made of concrete that embeds the wire, it absorbs and attenuates horizontally polarized waves and vertically polarized electromagnetic waves such as TV radio waves over a wide band, and also reduces the amount of ferrite magnetic material and reflective reinforcing bars used. By improving the cost and simultaneously reducing the overall weight, the handling is simplified and the conventional problems are solved.
[0034]
Next, a method for manufacturing a radio wave absorbing PC plate according to the present invention will be described.
A method of manufacturing a radio wave absorption PC plate according to the present invention includes a panel comprising a mortar layer forming a surface of a radio wave absorption PC plate, a cross-shaped radio wave absorber fixed to the mortar layer, and an anchor bar embedded in one end of the mortar layer. The unit is manufactured and placed in advance, and the panel unit is set in the form with the mortar layer facing down, and then concrete is placed in the form, ensuring radio wave absorption performance and quality. And productivity is improved.
Hereinafter, an embodiment of a manufacturing method of a radio wave absorption PC board by the present invention is described based on a drawing.
[0035]
The method for manufacturing a radio wave absorbing PC plate according to the present invention is configured by previously manufacturing and placing a predetermined number of the panel units 10 described with reference to FIGS.
Since the panel unit 10 manufactured in advance has a configuration in which the cross-shaped wave absorber 2 and the anchor bar 6 are integrated by the mortar layer 5 that forms the surface of the radio wave absorption PC plate, the mortar layer 5 is specially formed. There is no need for a shape or special processing, and a simple flat plate shape can be obtained, thereby reducing manufacturing costs.
[0036]
Further, by manufacturing the panel unit 10 in advance, the mortar layer 5 that is in a water-containing state at the time of manufacture can be surely dried from the reflector side of the cross-shaped wave absorber 2, so that the radio wave absorption performance is improved. And stabilization.
[0037]
Further, the panel unit 10 is provided with a connecting line 6A crossing the cross-shaped wave absorber 2 and a lattice line 6B along the longitudinal direction thereof, and is coupled to the upper chord member 7 and the lower chord member 8, It is possible to ensure the strength of the panel unit 10 that is long in one direction with the integrated structure, and to prevent warping deformation of the panel unit 10 during drying.
[0038]
5 and 6 show a manufacturing process of a radio wave absorption PC board according to the present invention.
In the manufacture of the radio wave absorbing PC plate according to the present invention, a predetermined number of panel units 10, 10,... Are assembled to a predetermined size as shown in FIG. Start with that. Each panel unit 10 is arranged with the front surface 4 of the mortar layer 5 forming the surface of the radio wave absorption PC plate facing downward, and a joint is formed between adjacent panel units 10 and 10. Joint material 17 such as sponge is arranged.
[0039]
Next, as shown in FIG. 6, after the panel unit 10 is set, desired reinforcing bars 18 and 18 are arranged at predetermined positions above the panel unit 10. Thereafter, concrete 19 is placed in the mold 16 to a predetermined level.
And after this concrete 19 hardens | cures and expresses predetermined intensity | strength, the formwork 16 is demolded and the joint material 17 is removed. The surface is formed by the front surfaces 4, 4,... Of the mortar layer, the panel units are integrated by the concrete 19, and the radio wave absorber PC plate 1 in which the cross-shaped wave absorbers 2, 2,. Is formed.
The concrete 19 may be various types such as ordinary concrete, lightweight concrete, fiber reinforced concrete.
[0040]
As described above, the method for manufacturing a radio wave absorption PC board according to the present invention uses a panel unit 10 whose surface is a front surface of a mortar layer to directly set tiles or the like as a panel material in a formwork as in the past. Compared with the case where it has been, it is possible to greatly reduce the labor of setting tiles and the like, and it is possible to improve productivity.
[0041]
Further, it is no longer necessary to strike mortar and concrete twice as in the prior art, and it is only necessary to place concrete 19 once in the mold 16, so that the construction efficiency can be improved even when placing concrete. Can do.
[0042]
In addition, in the manufacturing method of the radio wave absorption PC plate described in the above embodiment, the shape of the front surface 4 of the mortar layer forming the surface of the radio wave absorption PC plate, the reinforcing bar 6 is not limited to the configuration. It is also possible to attach tiles, stones, or the like on the front surface 4 of the mortar layer 5 or to provide a plurality of rows of cross-shaped wave absorbers on the panel unit 10.
[0043]
As described above, the present invention has been described in detail based on the embodiments. However, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention. It is natural that there is.
[0044]
【The invention's effect】
Electric wave absorption PC board of the present invention, embedded and桟型wave absorber, the mortar layer to form a surface of the radio wave absorber PC plate arranged in front of桟型wave absorber and桟型wave absorber and mortar layer Because it is made of concrete, it absorbs and attenuates electromagnetic waves over a wide band, improves manufacturing costs, and at the same time reduces the overall weight, making it easier to handle and preventing radio interference due to building reflections. Demonstrating.
[0045]
In addition, the radio wave absorption PC board of the present invention is characterized in that, in the above-described configuration, an anchor bar having one end side embedded in the mortar layer is planted, so that in addition to the above effects, integration with concrete is improved. Yes.
[0046]
Further, the radio wave absorption PC plate of the present invention has the above-described configuration in which the cross-shaped wave absorber is configured by disposing the cross-shaped ferrite magnetic body on the radio wave reflecting plate, and the length direction of the cross-shaped ferrite magnetic body is set to the television. It is arranged so that it is almost parallel to the magnetic field direction of the radio wave, and the height, thickness, and spacing of the cross-shaped ferrite magnetic body are related to the wavelength of the TV radio wave, the incident angle, the mortar layer in front of the ferrite magnetic body, etc. Since it is characterized by being set to a predetermined value, it effectively absorbs electromagnetic waves, prevents radio wave interference due to reflection of the building, and exhibits the effect of being lightweight and inexpensive to manufacture.
[0047]
The radio wave absorption PC plate according to the present invention is characterized in that, in the above configuration, the cross-shaped ferrite magnetic body is arranged in parallel on the radio wave reflection plate. It is improving.
[0048]
The radio wave absorption PC plate of the present invention is characterized in that, in the above configuration, the cross-shaped ferrite magnetic body is arranged in a grid pattern on the radio wave reflection plate, and the above effect is further improved by dealing with electromagnetic waves in all directions. It is improving.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a radio wave absorption PC board according to the present invention. FIG. 2 is a perspective view showing a panel unit constituting the radio wave absorption PC board. FIG. 3 is an elevational sectional view of the panel unit constituting the radio wave absorption PC board. FIG. 4 is a partial elevation view and arrow view for explaining the function of the radio wave absorption PC board according to the present invention. FIG. 5 shows a state in which the panel unit is arranged in the mold in the radio wave absorption PC board manufacturing method according to the present invention. Fig. 6 is a vertical sectional view showing a state in which concrete is placed in a mold in the method for manufacturing a radio wave absorption PC plate according to the present invention. Fig. 7 shows a conventional method for manufacturing a radio wave absorption PC plate. Elevated cross section [Fig. 8] Elevated cross section showing another example of conventional radio wave absorption PC board manufacturing method [Explanation of symbols]
1 Radio wave absorption PC board, 2 Cross-shaped radio wave absorber, 3 Concrete,
4 front of mortar layer, 5 mortar layer, 6 anchor muscle,
6A tether, 6B lattice, 7 upper chord, 8 lower chord,
10 panel unit, 11 cross-shaped ferrite magnetic body,
12 radio wave reflector, 13 gap filling material, 16 mold, 16a bottom surface,
17 Joint material, 18 Reinforcing bar, 19 Concrete,
30 electromagnetic wave absorption PC board, 31 mold, 31a bottom of mold,
32, 37 tiles, 33 ferrite plates, 34 reflective bars,
35 concrete, 36 anchor, 38 mortar,
39 Anchor muscle,

Claims (3)

A cross-shaped wave absorber,
A mortar layer that forms the surface of a radio wave absorbing precast concrete plate disposed in front of the cross-shaped wave absorber;
Concrete embedding the cross-shaped wave absorber and the mortar layer;
An anchor muscle having one end embedded in the mortar layer,
The cross-shaped electromagnetic wave absorber is configured by arranging a plurality of cross-shaped ferrite magnetic bodies on a radio wave reflector so that the length direction of the cross-shaped ferrite magnetic body is substantially parallel to the magnetic field direction of the television radio wave. And the height, thickness and spacing of the cross-shaped ferrite magnetic body are set to predetermined values in relation to the wavelength of the TV radio wave and the incident angle and the mortar layer on the front surface of the ferrite magnetic body, and A radio wave absorbing precast concrete board characterized by maintaining a space between a plurality of cross-shaped ferrite magnetic bodies by a gap filler.   The radio wave absorbing precast concrete plate according to claim 1, wherein the plurality of cross-shaped ferrite magnetic bodies are arranged in parallel on the radio wave reflecting plate.   The radio wave absorbing precast concrete plate according to claim 1, wherein the plurality of cross-shaped ferrite magnetic bodies are arranged in a grid pattern on the radio wave reflecting plate.

Images